The Determination of the Hexabromide and Iodine Numbers of Salmon Oil as a Means of Identifying the Species of Canned Salmon
Journal of Industrial & Engineering Chemistry
It is a well-established fact t h a t certain silicates of calcium and magnesium compare favorably with calcium and magnesium carbonates in neutralizing acidity and in their beneficial action upon soils.' Dana2 states t h a t gypsum occurs intermingled with limestone. Clarke3 says, "Wollastonite is commonly found as a product of contact metamorphism, especially in limestones;" also, "In many localities serpentine is associated with dolomite or dolomitic limestones." Taking all these factors
... l these factors into consideration it would appear that the acid-neutralizing power of the limestone as determined by titration is the best method t o use for determining the value of agricultural limes a n d limestones. SUMMARY I-The value of agricultural limes was determined by means of the acid-soluble calcium and magnesium, by means of COz determination with boiling hydrochloric acid, and b y digesting in standard acid and titrating the excess acid. 11-Pot cultures on two very acid soils were conducted using calcite, wollastonite, raw rock phosphate, gypsum, dolomite, magnesite, enstatite, and serpentine as correctors of soil acidity. 111-'Wheat and clover were grown in each soil and the crop increases reported. JV-Soil acidity was determined after cropping b y means of the Hopkins potassium nitrate method and the C. 13. Jones calcium acetate method. V-Crop increases due t o various treatments were obtained in t h e following order, the highest being placed first: Calcite, dolomite, magnesite, wollastonite, rock phosphate, serpentine, enstatite, and gY Psum. VI-The treatments decreased the soil acidity in the following order: Magnesite, dolomite, calcite, wollastonite, serpentine, rock phosphate, gypsum, and enstatite. VII-The results obtained in these experiments indicate t h a t the value of agricultural lime is in accordance with its acid-neutralizing power, rather t h a n with the CaO, MgO, or C o t contained, and t h a t the titration method is t h e most accurate and reliable method for determining the value of agricultural limes. S o a s AND CROPS DEPARTMENT A t the suggestion of Mr. H. M. Loomis, formerly of the Bureau of Chemistry, an examination of salmon oils for their chemical and physical characteristics was made in 191 j by L. B. Burnett in this laboratory. His preliminary experiments seemed t o indicate t h a t the iodine numbers and hexabromide values would furnish a method of distinguishing between the various salmon species. We have this year made a further study of oils expressed from canned salmon and believe t h a t the results we have obtained justify the assumption t h a t the oil from different species of salmon have characteristic iodine numbers and hexabromide values.